The SRI: a crucial indicator for eco-friendly buildings

The Solar Reflectance Index translates the ability of a material to reflect solar heat and exhibit a small increase in temperature when exposed to sunlight. Its scale ranges from 0 to 100:

• The value 0 corresponds to that of a black reference material (very little reflectance and capability of emitting the absorbed heat) whose initial reflectance is 0.5 and the emissivity is 0.90,
• The value 100 corresponds to that of a white reference material (very reflective and capable of emitting a small amount of stored heat) whose initial reflectance is 0.80 and the initial emissivity is 0.90.

It is noted that the calculation of the IRS requires prior knowledge of albedo and emissivity.

It is for this reason that the IRS is widely used in the field of environment and building. Indeed, the building materials used on the facade of buildings can contribute to :

1. Reduce the need for air conditioning in hot areas;
2. Reduce the effect of the “urban heat islands” phenomenon (this term refers to local temperature increases, particularly maximum daytime and nighttime temperatures, recreation in urban areas compared to rural or forest areas, or relatively to regional temperature regional average).

For more information on measuring albedo, click here!